There are known mechanisms for releasably holding a toolholder shank in a support block bore when the mechanism actuating member is transversely aligned with respect to the longitudinal axis of the toolholder shank and a support block bore. Such mechanisms and articles are used in the cutting and shaping of workpieces where it is not expedient to use the tool support block in connection with a base member having a bore containing an axially aligned power driven means for axially actuating the locking mechanism in the tool support block. Examples of toolholders and support blocks utilizing releasable locking mechanisms having radial activation are shown in U.S. Pat. Nos. 4,573,824; 4,575,293 and 4,135,418 and 4,736,659.
Conventional cutting units and clamping mechanisms in some tool holder assemblies use a key and key slot for radial location of the cutting tool. The tolerances involved allow for various amounts of clearance that can lead to radial inaccuracies that, in turn, can be a problem in certain machining applications. The dimensions and tolerances currently in use are at their practical limit. Tighter tolerances and smaller clearances would require extra machining operations, thereby increasing the cost of the system.
Accordingly, there is a need for an improved mechanism in this field for aligning the toolholder and the clamping unit, thereby reducing or eliminating any variance in the radial location of the cutting tool.